How to clone a texture from other UV Map Image in the Texture Paint Mode in Blender 2.77a?
I finally found out how to set the Clone.



Steps

The following step is under Blender 2.77a in Ubuntu.


Go to Texture Paint mode.


According to the following image, you can click Brush -> Image Paint Tool -> Clone.


Set the Brush to clone.


Go to Option and configure the setting like the following.


Go to Slots and select the Paint Mode as Image.


Create a new Canvas Image and rename it as what you want. e.g. Casper Texture.


Set the UV Map you want to paint it to.


Check the checkbox Clone from image/UV map.


Select the Source Clone UV/Map.


Select the image of the UV/Map you want to clone.


Paint it.


Save your painted UV/Map image.






References


Blender - "Micky" Ch.1 - Pt. 9 - Texture painting with Clone Brush